利用全固态分子束外延方法在Ge(100)衬底上异质外延GaAs薄膜及相关特性表征

利用全固态分子束外延(MBE)方法在Ge(100)衬底上异质外延GaAs薄膜,并通过高能电子衍射(RHEED)、高分辨X射线衍射(XRD),原子力显微镜等手段研究了不同生长参数对外延层的影响.RHEED显示在较高的生长温度或较低的生长速率下,低温GaAs成核层呈现层状生长模式.同时降低生长温度和生长速率会使GaAs薄膜的XRD摇摆曲线半高宽(FWHM)减小,并降低外延层表面的粗糙度,这主要是由于衬底和外延薄膜之间的晶格失配度减小的结果.

Initial heteroepitaxial growth and characterization of GaAs on Ge(100) by all-solid-source molecular beam epitaxy

The initial heteroepitaxial growth stages of GaAs on Ge(100) by all-solid-source molecular beam epitaxy(MBE) were studied by means of reflection high-energy electron diffraction (RHEED), high resolution X-ray diffraction (XRD) and atomic force microscopy, as well as the effects of different growth conditions to the epitaxial layer qualities. It was indicated that high growth temperatures or low growth rates enabled a layer-by-layer growth mode of initial GaAs nucleation layer which was evidenced by RHEED patterns. However, the combination of low growth temperatures and low growth rates for the initial GaAs layer gave lower full-width at half-maximum value of rocking curves and lower surface roughness of the epitaxial materials, owing to the decrease of the lattice mismatch between substrates and epi-layers.